A negative active material for a rechargeable lithium battery includes a secondary particle in which a plurality of natural graphite primary particles are agglomerated, the plurality of primary particles including natural graphite, and the secondary particle including pores, and an amorphous carbon positioned in the pores, wherein an area of the amorphous carbon is about 10% to about 30% based on a total area of 100% of the negative active material, in a cross-section of the negative active material.